New York (CNN) — A New York college professor was beheaded and her body dumped outside an apartment building by her son, who later killed himself by stepping in front of a commuter train, police said.

The woman has been tentatively identified as Patricia Ward, a 66-year-old assistant professor at Farmingdale State College on Long Island, Detective Lt. John Azzata of the Nassau County Police told reporters Wednesday.

She was decapitated shortly before 8 p.m. Tuesday by Derek Ward, 35, with a kitchen knife in the second-floor apartment they shared, Azzata said. Patricia Ward had multiple stab wounds and broken ribs, police said.

The son either carried or dragged his mother’s body down the stairs, through the lobby and left it on the street, Azzata said. Her head was found about five feet from the body, leaving some neighbors to think the gruesome scene was a Halloween stunt.

“I literally thought it was a prank,” one resident said, according to CNN affiliate WCBS. “We saw the body on one side and saw the head on the other side. I thought everything was a prank.”

Less than a half hour after his mother’s body was found, Derek Ward apparently jumped in front of a Long Island Rail Road train heading east from Penn Station in Manhattan, police said.

“It appears that this is a murder-suicide,” Azzata said.

Patricia Ward was an assistant professor of language arts at the college’s Long Island Educational Opportunity Center, which helps high school students prepare for college.

“Patricia Ward was a member of the campus for 28 years,” Patrick Calabria, the college vice president for institutional advancement and enrollment, said in a statement. “She was well-known, well-liked and well-respected. The campus is a very sad place today.”

Derek Ward, who was unemployed, had a history of psychiatric problems dating back 10 years, his condition exacerbated in the last years after the death of his maternal grandfather, according to Azzata.

Police said there were no reported domestic incidents at the Ward home.

Derek Ward had a 2003 arrest for criminal mischief and received a fine and probation, Azzata said.

In 2006, Derek Ward was arrested for criminal possession of a 9mm Smith & Wesson handgun as well as a drug charge, Azzata said. He received a 45-day sentence and three years’ probation.

“It’s insane,” a Farmingdale resident said of the murder-suicide, according to WCBS. “You never think something like that’s going to happen right outside your doorstep.”

The motive is under investigation.

“We did not know anything about her family life,” Calabria told CNN. “We are all in shock.”